If you’ve ever looked at a shampoo, body wash or cleanser ingredient list, you may have spotted these two:
Sodium Lauryl Sulphate (SLS)
Sodium Laureth Sulphate (SLES)
At first glance, they look almost identical.
In fact, you’d be forgiven for thinking one of them was a typo.
But while SLS and SLES are closely related and do similar jobs, they’re not exactly the same. If you’re formulating your own products, knowing the difference can help you choose the right one.
So, let’s settle the SLS vs SLES confusion once and for all.
First: What Do They Actually Do?
Both SLS and SLES are anionic surfactants.
Surfactants help water lift away oils, dirt and other substances it wouldn’t easily remove on its own. They’re also responsible for much of that lovely cleansing and foaming action we expect from shampoos, body washes and hand washes.
In simple terms:
They help products clean, spread and foam. So far, they’re sounding pretty similar.
Meet SLS: The Enthusiastic Cleaner
Sodium Lauryl Sulphate (SLS) is a strong and effective surfactant known for excellent foaming, cleansing and degreasing.
Basically, SLS came to clean and it means business.
That makes it useful when stronger cleansing is needed, but there is a trade-off. Its stronger cleansing action can also make it feel more drying or irritating, particularly in frequent-use products or formulations where mildness is important.
Think of SLS as the enthusiastic cleaner of the two.
It gets the job done. It gets everything done. It may even clean things you weren't planning on cleaning.
For products aimed at dry or sensitive skin and scalps, a milder surfactant system may therefore be preferable.
At Brightpack, you’ll find SLS in two very different-looking forms: SLS 28 and SLS Needles.
SLS 28 is a liquid grade containing approximately 28% active SLS, making it convenient to incorporate into liquid formulations.
SLS Needles, on the other hand, are a highly concentrated solid form of SLS. Same surfactant, very different format, so they shouldn’t simply be swapped gram-for-gram in a formulation.
And yes, they really do look like little needles. Chemistry wasn’t feeling particularly creative with the name.
Meet SLES: SLS's Milder Relative
Sodium Laureth Sulphate (SLES) is closely related to SLS, but its structure has been modified through a process called ethoxylation.
This changes how the surfactant behaves and generally makes SLES milder than SLS, while still giving you effective cleansing and plenty of foam.
That’s one reason you’ll commonly find it in:
Shampoos | Body washes | Hand washes | Cleansers
SLES also works well alongside surfactants such as Cocamidopropyl Betaine (CAPB), which can help improve mildness, foam quality and viscosity.
At Brightpack, one of the grades you’ll come across is SLES 25. The “25” refers to its approximate active concentration, around 25% active SLES in the supplied material.
So SLES 25 isn’t a different surfactant from SLES. It’s simply telling you something important about the grade and concentration you’re working with.
Same family. Similar job. Slightly different personality.
SLS vs SLES: The Quick Version
| SLS | SLES | |
|---|---|---|
| Full name | Sodium Lauryl Sulphate | Sodium Laureth Sulphate |
| Type | Anionic surfactant | Anionic surfactant |
| Cleansing | Strong | Effective, generally milder |
| Foaming | Excellent | Excellent |
| Mildness | Can be more drying/irritating | Generally milder than SLS |
| Common uses | Cleansers & cleaning formulations | Shampoos, body washes, hand washes & cleansers |
| Brightpack examples | SLS 28 & SLS Needles | SLES 25 |
The easiest way to remember it?
Lauryl = SLS = stronger cleansing
Laureth = SLES = modified to be milder
Wait… What Do 25 and 28 Actually Mean?
This is an important one.
When you see names such as SLS 28 or SLES 25, the number refers to the approximate percentage of active surfactant in the supplied raw material.
So:
SLS 28 → approximately 28% active SLS
SLES 25 → approximately 25% active SLES
SLS Needles → a much more concentrated solid form of SLS
That matters when formulating. Two raw materials may perform a similar job, but if their active concentrations are different, you can’t assume you should use the same amount.
In other words: always formulate according to the specific grade you’re actually using.
But Aren't Sulphates Bad?
Ah, the dreaded S-word.
With so many products proudly displaying “SULPHATE-FREE” on the label, it’s easy to assume that sulphates are automatically something you should avoid.
But is that actually the case? Well… that’s a whole blog on its own.
There’s a lot more to the sulphate debate than a simple good ingredient vs bad ingredient answer. Concentration, formulation, product type and the combination of surfactants all play a role.
For now, the important thing to know is that SLS and SLES are both surfactants, and they’re not quite the same.
So, Which One Should You Choose?
There isn't one universal winner.
If you need stronger cleansing and degreasing, SLS may be suitable. If you want effective cleansing and foam with a generally milder profile, SLES may be a better starting point.
You can even use SLS and SLES together. This can help balance stronger cleansing from SLS with the relatively milder cleansing and rich foam of SLES.
And remember: your surfactant is only one part of the formula. How mild, thick, foamy or cleansing your finished product feels depends on the entire formulation.
Similar Names. Different Personalities.
SLS and SLES may look almost identical on an ingredient list, but now you know they’re doing things a little differently behind the scenes.
So next time you spot Sodium Lauryl Sulphate and Sodium Laureth Sulphate, there’s no need to squint at the label wondering whether somebody made a typo.
Similar names. Same family. Different personalities.